Detection of Leishmania braziliensis in naturally infected individual sandflies by the polymerase chain reaction

The natural infection of sandflies by Leishmania in wild-caught specimens w as studied, using the polymerase chain reaction (PCR)-hybridization techniq ue. The PCR was carried out using 2 oligonucleotides (primers 3J1 and 3J2) derived from a repetitive nuclear DNA sequence. The primers support the enz ymatic amplification of a fragment of approximately 500 bp, present in the nuclear DNA of Leishmania braziliensis. The expected band was observed in 5 of 65 sandflies containing flagellates. After hybridization with a species -specific probe, we confirmed natural infection by L. braziliensis. The tec hnique allowed the identification of Lutzomyia gomezi and Lu. panamensis as vectors of L. braziliensis in an endemic area of cutaneous leishmaniasis i n Urama, Puerto Cabello district in Venezuela. As far as we are aware, this work constitutes the first report of natural infection of Lu. panamensis w ith L. braziliensis in the study area. We also demonstrate that PCR-hybridi zation is a suitable approach to establish the Leishmania-sandfly relations hip and will be useful in epidemiological studies of leishmaniasis in endem ic areas.